In the first year of this grant this laboratory has developed a general computer program for adaptive control of large pharmacokinetic models, making large linear or nonlinear compartmental models, and for simulation and parameter identification, using the method of weighted least squares. A fast version for simpler models has also been developed. It is now planned to: 1. Acquire experience with these programs in clinical situations (adaptive control of gentamicin, digitalis, and antiarrhythmic therapy, for example), to see where and how these programs can be misused, to develop them into useful clinical tools for adaptive control of drug therapy. 2. Depart from strict compartmental analyses when needed, to examine "input-output" techniques and methods of "control without identification" to increase the capability of adaptive control of drug regimens. 3. To incorporate these new clinical programs, as they are developed, into the current USC PACK collection of time-shared programs for community hospital use.